Problem: $ { {-2} \times \left[\begin{array}{r}{-1} \\ {2} \\ {0}\end{array}\right] = {?} } $
To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{r}{-2}\times{-1} \\ {-2}\times{2} \\ {-2}\times{0}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{r}{2} \\ {-4} \\ {0}\end{array}\right]}$